While this is a simple feature that most LabVIEW users will know about, its an amazingly useful feature for those who have not been introduced to it yet. Highlight execution will literally slow down your code, and give you a visual representation of the "data flow" through the wires on your block diagram. This is extremely useful for finding race conditions, watching execution order, or troubleshooting your VI.
Steps to Complete
All that is needed to do to enable highlight execution is click on the lightbulb on the toolbar of the block diagram. Once you are done watching your code, feel free to click the lightbulb again at any time to disable the highlight execution.
Or you can check out a quick video on my blog to see how to do it for yourself!
Be CAREFUL with highlight execution in subVIs. If you turn it on in the subVI, and then close that subVI and save it, your main VI will appear to "hang" while it is waiting for your subVI to complete with highlight execution turned on.
Also, note that highlight execution physically slows down your VI. So, if you're trying to do something time-critical, don't be surprised if your results are off!